Many of today's electronic goods contain one or more electronic components that operate at elevated temperature requiring some type of thermal management system. By way of example, portable computers and wireless phones have one or more microelectronic packages that generate a considerable amount of thermal energy dissipated as heat. An example of a microelectronic package is an integrated circuit microprocessor, an example of which is a central processing unit (CPU) for the computer system.
In some cases, the heat can be managed with a thermally coupled heat sink, which provides a large surface area for dissipation of heat through convection. Heat sinks are generally formed from a material having a high thermal conductivity. Heat sinks couple with the microelectronic package and comprises a plurality of fins or pins through which air may pass to dissipate the heat. In many cases, a fan is attached to the heat sink to provide forced convection for more efficient heat dissipation.
With the drive for smaller electronic products, the available space is very limited to house a heat sink and fan. In some cases the heat sink is remotely located or a different thermal management solution used. For example, in some portable computers, such as laptop computers, heat generated from the electronic components is carried via heat pipe to a remote heat sink, commonly located in the hinge connecting the display to the base.
In some cases, the heat dissipation device is a flat plate known as a heat spreader. The amount of thermal dissipation remains limited in these devices due to high thermal resistance related to the thermal mass of a solid metal plate and the limited efficiencies of passive convection.
In yet another example, the microelectronic components within a wireless phone generate significant amounts of heat during use that must be dissipated to prevent damage. The concentrated heating and small size of the enclosure make thermal management a significant issue in wireless phone design.
New apparatus and methods are needed for providing thermal management of space-limited electronic devices. They must provide for small scale integration, be capable of managing the thermal requirements of the electronic device, not significantly impact the electrical power consumption of the device, and be inexpensive to manufacture.